GNGTS 2018 - 37° Convegno Nazionale

574 GNGTS 2018 S essione 3.1 of the model and reflecting boundary conditions at the top side to simulate the sea-air interface. The order of approximation of the spatial derivatives is optimized to reduce the numerical dispersion (Galuzzi et al. , 2017). The source wavelet is estimated from the sea-bed reflection. Design of a robust misfit function . Before performing the Full Waveform Inversion, dedicated processing operations are applied on both predicted and observed seismograms to reduce the cycle skipping effect and, in general, to circumvent the non-linearity of the optimization problem. As shown in previous studies (Galuzzi et al. , 2018) (Mazzotti et al. , Fig. 1 - (a) Location of the M12A CROP profile. The red arrow represents the part of the profile used for the inver- sion. (b) An example of shot gather used in the inversion. The red polygon delimits the portion of the seismogram considered in the inversion. Fig. 2 - a) Velocity model obtained by the MVA. b) Velocity model obtained at the end of the FWI optimization procedure.